Various devices, apparatus and systems have been used and are known in the prior art for determining the camber and caster of vehicle wheels. Caster is the backward tilt of the axle or the member holding the wheel and camber is the outward tilt of the top of the wheel. Caster and camber are utilized in order to provide for ease of steerage of the vehicle and produce a minimal amount of wear on the vehicle tires. The various systems and apparatus known in the prior art have generally been quite complicated, difficult to use, and generally expensive. Furthermore, the previously known devices were of questionable reliability except for the most expensive and sophisticated systems.
Within recent years, increased emphasis has been placed upon the desirability of aligning large wheels, such as those found upon buses and trucks. Vehicles of this type are usually aligned by driving the vehicles onto wheel turntables located on the runways of pit, power and drive-on racks. The use of racks enables the alignment operator to make the necessary adjustment without undue bending. Additionally, improved access is provided to the underside of the vehicle to enable the necessary alignment corrections to be made. However, such racks are also complicated to use, can be dangerous, and are somewhat unreliable.
In the past, a large number of patents have dealt with devices that have been used for the alignment of wheels. U.S. Pat. No. 2,137,485, issued on Nov. 22, 1938, to Greenleaf et al. discloses a wheel alignment device which is attached directly to the side of wheel while it is in place on its axle. An indicator is provided so as to indicate normal caster, camber, turning radius or toe-in positions. U.S. Pat. No. 2,608,368, issued on Aug. 26, 1952, to Bagge et al. shows a wheel gage mounting device for determining the camber and caster of front wheels of vehicles. The device is mounted on the wheel spindle. U.S. Pat. No. 3,079,695, issued on Mar. 5, 1963, to Mineck discloses a wheel alignment device in which the wheels are supported on flat tables supported on casters. A vertical extension extends upwardly from the tables so as to measure caster and camber. U.S. Pat. No. 3,488,857, issued on Mar. 13, 1970, to J. R. Bateman provides a wheel alignment apparatus having support legs with interchangable adapters for connection to either spindles of the steerable wheels of an automotive vehicle or to the drums that ordinarily mount the wheel. U.S. Pat. No. 4,271,599, issued on Jun. 9, 1981, to F. C. Pavitt discloses an apparatus for use in measuring the camber and caster of a motor vehicle wheel. This apparatus comprises two slidably adjustable parallel rods which engage either the rim of the vehicle wheel or the suspension members. A spirit level is used to measure the inclination of the rods relative to the horizontal for determining the caster or camber of the wheel. U.S. Pat. No. 3,292,268, issued on Dec. 20, 1966, to H. L. Knight discloses an automobile front wheel alignment mechanism having a frame for mounting on the outer side wall of the front wheel tires of an automotive vehicle. A pendulum means is suspended from an upper portion of the fixed frame and has an elongated bottom member arranged for metering cooperation with the scale means. U.S. Pat. No. 3,443,318, issued on May 13, 1969, to C. W. MacMillan shows an apparatus for electrically measuring the toe of vehicle wheels having a pair of toe arms suspended from the front wheel of the vehicle and carrying a pendulum which is movable about a vertical axis. An electromagnet is associated with the pendulum for producing a current which is representative of the angular position of the pendulum and, thus, a measure of the toe of the vehicle wheel. U.S. Pat. No. 3,648,375, issued on Mar. 14, 1972, to E. D. Wilkerson provides a support for a portable wheel aligner unit to carry adjustably the aligner unit from a storage position to a position adjacent the vehicle wheel to be aligned. U.S. Pat. No. 4,569,140, issued on Feb. 11, 1986, to J. A. Hobson discloses a thrust line wheel alignment apparatus and method which relies upon a stationary reference "halo" so as to measure vehicle wheel alignment.
It is an object of the present invention to provide a portable wheel aligner device which is suitable for the measure of caster, camber, and toe-in of a vehicle wheel.
It is another object of the present invention to provide a portable wheel alignment measuring device which is easy to use, simple to manufacture, and relatively inexpensive.
It is another object of the present invention to provide a device for the measuring of wheel alignment which is adaptable to various sizes of vehicle wheels.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.